Microscopes vary is size and complexity. Typically, the delivery of excitation and/or illumination radiation to a sample in a microscopy system requires complicated optical components that direct and redirect the radiation from a source through the microscope system to the sample. Translation of the sample (e.g., for focusing the sample to an objective lens of the microscope) can interfere with the positioning of the delivered radiation. In several applications the angle of delivery of the radiation to the sample and/or a sample slide are critical to the results of the microscopy method. When the sample platform is moved with relation to the radiation delivery mechanisms, the delivery mechanisms may require readjustment to ensure the proper delivery of the radiation to the sample. Further, modifying an existing microscope to perform certain specific microscopy methods (e.g., total internal reflection (TIR) microscopy) can be a costly and complex process.
Total internal reflection (TIR) occurs when electromagnetic radiation (EMR), typically light, strikes an interface between two optical media at an incident angle equal to, or greater than the critical angle. FIG. 1 illustrates one example of TIR at an interface 110 between a glass microscope sample slide 120 and a sample 130. The incoming beam of electromagnetic radiation (EMR) 140 is incident at interface 110 at a critical angle 150. TIR energy 160 is reflected, and an evanescent field 170 is thereby produced and emanates into sample 130. The critical angle for TIR at an interface of a first and second material can be given as:θc=sin−1(n2/n1), where n1>n2,where n1 is the refractive index of the first material, n2 is the refractive index of the second material, and Θc is the critical angle.